All things related to multicast

[John Zwiebel <>]

If your network is going to strictly pass multicast packets between
sites such that the only need for an RP is to: a) originate MSDP
messages for sources that have registered with a particular RP and;
b) to allow receivers to always join to the SPT, then option 2 is the
best choice.  This is also the choice of major ISPs which only transit
multicast traffic and never (or very rarely) originated traffic inside 
their
PIM domain.

NOTE: there is "no such thing" as a shared-tree between
PIM domains.  It is theoretically possible to set this up, but would
require some administrative cooperation between PIM domains to
ensure allocation of multicast groups to a particular RP address --
and in that case, you should probably not use anycast-RP since
you would then have two or more roots on the shared-tree with
each root having to join to the SPT for each source, causing that
SPT to cross some branches of the shared-path of the other anycast
RPs leading to all kinds of problems you don't want to have to
think about.

Neither is there any way for an anycast-RP member to set up a
"SPT-like" forwarding path that only goes to the other anycast-RP
members.

If you are considering providing RP services to several customers,
so you can set up interdomain shared-trees, well, you'lll be blazing
a new trail.

However, you may have the administrative control over all multicast
within your association of networks.  (I doubt it)  In this case, you 
may
consider option 1.

Option 3 doesn't provide you anything that option 2 doesn't and just
makes life more complicated.

The point is, the most efficient distribution of mpackets across a large
network is going to be through setting up shortest-path trees.  The
"best" way of making this happen with ASM (or ISM) is with anycast-RP.

A "better" way of making this happen is to convince your application
developers that you want IGMPv3 and SSM.

On Tuesday, November 19, 2002, at 01:21 AM, Danijela Bedic wrote:

> I'm writting mcast implementation proposal for national academic 
> network in Croatia. / CARNet /
>
> I'm interested in your experience with RP configurations because I'm 
> not shure which is best to implement:
>
>  
>
> 1.)    Auto-RP  with Static RP as backup
>
> 2.)    Anycast static RP
>
> 3.)    Anycast with Auto-RP configuration
>
>  
>
> Regards,
>
>  
>
>                         Danijela
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> *************************************************
>
> Danijela Bedić, dipl.ing.el.
>
> CARNet - R&D Lab
>
> tel. +385 1 6313 074
>
> CROATIA
>
> mailto: 
>
>
> *************************************************
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